dan bongino's job when he was at the secret service, protect president obama with 1.8 million people on the washington mall gathered for his first inauguration. >> you can't guarantee anything. all do you in the field of security is reduce the probability of an event like this to hopefully something so miniscule so if something happens your response afterwards is enough to keep the casualties to a minimum. >> if this turns out to be domestic or international terrorism it will remind people of the difficulty of the task that we have been working against over the past ten years. >> reporter: security experts say that over the last 11 or 12 years as we've gotten farther and farther away from 9/11 americans have grown tired of being hassled by the tsa and the security at sporting events and this soft target a marathon underscores the fact that these threats remain very real. >> tom costello in washington for us this morning. >>> bill bratton is the former police commissioner in new york and served in los angeles as well. good morning. >> good morning. >> i know this strikes close to home